This invention relates to a process for conversion of a low molecular paraffin hydrocarbon to an aromatic hydrocarbon. More particularly, it relates to a process for conversion of a low molecular paraffin hydrocarbon of 5 or less carbon atoms such as ethane, propane, butane, pentane or a mixture thereof to an aromatic hydrocarbon.
Utilization of low molecular paraffin hydrocarbons contained in natural gas and light paraffin hydrocarbons produced from petroleum refining process is an important problem because these hydrocarbons are produced in large amounts.
Recently, there have been reported many processes to convert ethane to aromatic hydrocarbons with ion-exchanged H-ZSM-5 catalysts. For example, Mobil Oil Corporation has reported use of Cu-Zn/H-ZSH-5 catalysts in U.S. Pat. No. 4,120,910 (1978). Mobil Oil Corporation has further reported use of Ga/H-ZSM-5 catalysts in U.S. Pat. No. 4,350,835 (1982). Moreover, use of gallium-exchanged aliminosilicate has been reported in EPC Application No. 50,021.
However, according to the conventional processes, both the conversion of ethane and selecting to aromatic hydrocarbons are not high and improvement of catalysts and research of reaction characteristics have been required. For these reasons, researches have been made on novel catalysts for selective conversion of lower molecular paraffin hydrocarbons such as propane to liquid fuels or aromatic hydrocarbons.
The inventor has already made researches on process for producing aluminosilicate catalysts as disclosed in U. S. Pat. No. 4,400,328 (Aug. 23, 1983).
It has now been found that a catalyst comprising a combination of said metallo-silicate catalyst excellent in selectivity of catalyst form and a catalyst having dehydrogenation function and a gallium-silicate catalyst can convert low molecular paraffin hydrocarbons to aromatic hydrocarbons at a high conversion and a high selectivity.